Daytona 500 Testing: Whoa, Boys! NASCAR Shrinks Restrictor Plates

In the constant struggle to regulate speeds at Daytona, NASCAR announced on Wednesday that it will decrease the size of the restrictor plates for the upcoming test at Daytona International Speedway.

The restrictor plates are designed to reduce airflow into the carburetor which in turn reduces horsepower at Daytona and Talladega, the sister tracks where speeds are traditionally the highest on the schedule.

During last month's Goodyear tire test at Daytona, teams were using a 30/32 of an inch plate, and for the January test the plate size will be dropped to 29/32 of an inch.

After the December test, Vice President of Competition Robin Pemberton hinted that NASCAR may reevaluate the size of the plates going into the next session slated for January 20-22.

"We're not sure if we may need to come down a little bit off of that, which would be like a 64th of an inch or something. But we'll have to get back and talk to the teams and look at the speeds from the last two days of testing."

The last race at Daytona in July of 2010 featured the largest aperture in the plates since their introduction back in 1988. The plates measured one and 1/32 of an inch. The move to a larger plate in July was made in part due to the added drag of the blade style spoiler that was introduced on the Car of Tomorrow last season.

Qualifying was rained out for that race, but in the final practice Robby Gordon posted a speed of 195.126 MPH.

With a smaller plate size, cooler temperatures and a wing spoiler, Jeff Burton posted the fastest speed in final practice for the 2010 Daytona 500 at 195.194 MPH.

Last month's test with the 30/32 inch plate and the new surface produced speeds in excess of 197 MPH in the draft, despite most participants not bringing their primary Daytona 500 equipment.

The sanctioning body has been in an arms race with the teams over the years, as engine builders have found ways to increase horsepower, NASCAR has tried to regulate it with the size of the plates.